Telephone system



May 19, 1931. R. LJ MAURER TELEPHONE SYSTEM 7 Filed May 29,1929

mm H m Patented May 19, 1931 UNITED STATES PATENT OFFICE RUSSELL L.MAURER, OF CHICAGO, ILLINOIS, ASSIGNOR OF ONE-FOURTH TO GEORGE E.MUELLER, OF CHICAGO, ILLINOIS TELEPHONE SYSTEM,

Application filed May 29,

My invention relates to a telephone system and more particularly to asystem having means for mechanically interconnecting a local telephonesystem with an outside telephone system. a

In many cases it is convenient or desirable to have a private telephonesystem in a manufacturing or business establishment for communicatingbetween the various departments.

19 Such a system if privately owned is not subject to charges usuallymade by telephone companies for this service. However it often becomesnecessary to communicate with outside parties and in view of the factthat telephone companies do not permit electrical connection to be madewith their apparatus I have devised a means for establishing amechanical connection between any one of a number of telephones in aprivate system and an outside telephone.

An object of the invention is to provide a new and improved telephonesystem. A further object is to provide a simple a and eflectiveapparatus for mechanically establishing communication between anextension or local telephone and an outside telephone system.

A further object is to provide a connecting telephone having a remotecontrol for mak- 50 ing the necessary operating conections.

A further object is to provide a remote control apparatus forcontrolling a master telephone and a connecting or repeating tele-.

phone mechanically associated therewith. In accordance with the generalfeatures of the invention a connecting telephone is mechanicallyassociated with a master telephone connected to an outside telephonesystem and a link circuit is provided for connecting any one of a numberof extension telephones with each other or to the connecting telephoneto establish communication between an extension telephone and the mastertelephone system. l

The single figure of the drawing is a schematic diagram of a telephonesystem embodying the invention. The apparatus comprises in general a nmaster telephone M connected to an outgoing telephone system, aconnecting or repeating 1929. Serial No. 366,932.

telephone M mechanically associated therewith, a plurality of extensiontelephones N and N only one of which is shown in full, and a cordcircuit C for interconnecting the extension telephones with each otheror with the repeating telephone M.

The master telephone M may be of any suitable type and includes theusual transmitter 9 andreceiver 10. The receiver 10 is normally removedfrom the receiver hook 11 but the receiver hook is yieldingly held inits normal or down position by an armature 22 actuated bya spring 12. Areceiver 13 of the connecting telephone M is placedin close proximity tothe transmitter 9 of the master telephone M so that the sound producedin the receiver 13 is communicated to the transmitter 9, and thetransmitter 14 of the connecting telephone M is placed in closeproximity to the receiver 10 of the master telephone M so that the soundproduced in the receiver 10 is communicated to the transmitter 14. Inthe connecting telephone illustrated, the receiver 13 is in series withthe secondary of'an induction coil 15 the primary of which is connectedacross the talking lines 16. A condenser 17 is provided in the receivercircuit to prevent direct current from flowing through the receiver. Inorder to disconnect the receiver and transmitter of the connectingtelephone when the telephone is not in use a pair of contacts 18 isprovided which are adapted to be placed in series with the transmitter14 by an armature 19 actuated by an electromagnet 21. Armature 22 isalso associated with the electromagnet 21 and serves to raise thereceiver hook 11 to connect the master telephone with the line L whenthe electromagnet 21 is energized. 'vVhile two armatures 19 and 22 areshown it will be understood that in practice a single armature may beused to accomplish the functions of both. The electromagnet 21 isenergized by a battery 23 which is grounded at 24. t

' Extension telephones N and N are shown as of the common battery systemtype having a transmitter 25 and receiver 26 and receiver being normallyplaced on hook .20. Line conductors 27 lead from the extension telephoneto a jack 28. A pair of contacts 29 are normally engaged by springcontact arms of the ack and lead through a relay 31 having two windings,to opposite poles of a battery 33 one pole of which is grounded at 32.Relay 31 with armature serves in one of its functions as a relay whichwhen closed lights a line signal lamp 34 from a battery 35. It will beseen that when receiver 26 is re moved from its hook a circuit will beestab lished from battery 33 through the upper winding of relay 31 toone contact 29; ack 23, transmitter 25, receiver 26 through the otherside of jack 28, contact 29 through thelower winding of relay 31 toground 32 thus energizing the relay to light the signal lamp 34.

Although a number of batteries are shown in the drawing it is to beunderstood this is simply as a matter of convenience and they arepreferably one and the same battery.

The cord circuit C comprises talking conductors 41 and 42 terminating ina pair of plugs 43 and 44. lVhen the plug 43 is inserted in the jack 28in response to the lighting of line lamp 34 when a call is made, thecontacts 29 will be broken to deenergize the relay 31 and extinguish theline lamp 34. At the same time contact 45 of plug 43 will be groundedthrough the jack sleeve tending to establish a circuit from battery 47through contact 48, supervisory lamp 49, to ground. However, when theplug 43 is inserted in jack 28 relay 51 will be energized to open thecircuit of contact 48 and prevent the supervisory lamp 49 from beinglighted. The battery 47 is connected at its opposite poles through theupper and lower windings of relay 51 to the lines 41 and 42 to supplytalking current to the extension telephone. The breaking of the circuitin the extension telephone due to returning the receiver to its hookwill interrupt the circuit through relay 51 and light the supervisorylamp until the plug 43 is removed from jack 28.

An operators telephone 52 is connected across conductors 41 and 42through a key 53. hen a signal is received from an extension telephoneby the lighting of the line signal lamp the operator inserts the plug 43in jack 28 and upon ascertaining that an outside party is wanted insertsplug 44 in jack 54 connecting the talking conductors 41 and 42 to theconductors 16 of the connecting or repeating telephone. Jack 54 isprovided with a spring contact 55 which is insulated from the contactarms of the jack and engages a contact member 56 grounded at 57 whenplug 44 is inserted in the jack. The engagement of spring contact 55with the contact 56 establishes a circuit from battery 23 throughelectromagnet 21, spring contact 55, contact 56 to ground 57 thusenergizing the electromagnet 21 and actuating armatures 19 and 22 toestablish electrical communicating connections in the master telephone Mand repeating telephone M. The talking current for the connectingtelephone is supplied by abattery 61 the opposite poles of which areconnected through a relay 62 to conductors 41 and 42. A contact 63 isassociated with relay 62 and connects the battery 61 through asupervisory lamp 64 to the ground 65' of the sleeve of jack 64. Thissupervisory lamp is not lighted when the plug 44 is connected to thejack 54 and serves no function unless the link circuit is used tointerconnect a pair of extension telephones. Suitable condensers 66 and67 are provided in thelines 41 and 42 of the link circuit to preventdirect current from flowing therein as is well known in the art.

The operation of the apparatus is as follows:

When a call comes in from the master telephone M the operator hears thebell of this telephone and inserts the plug 44 in jack 54 to raise thereceiver hook of telephone M and establish the proper electricalconnections in the telephone MC The operator then actuates key 53 toconnect the operators telephone and upon learning the name of the partybeing called inserts the plug 43 in the jack 28 of the proper extensiontelephone causing the supervisory lamp 49 to be lighted until thereceiver of the extension telephone is removed. In order to call theparty at the extension telephone a ringing key 71 is provided having aground 72 and a source of ringing current 73. When the call is ended thesupervisory lamp 49 will again be lighted by the receiver of theextension telephone being placed upon its hook- The operator thenwithdraws plugs 4344 thereby deenergizing magnet 21 to restore switchhook 11 to open the circuit of line L thereby givingthe usual disconnectsignal to the operator at the main exchange so that the connection theremay be taken down in the usual manner.

A call originatingat anextension telephone causes theline lamp 34 to belighted which is extinguished as soon as the plug 43 is inserted in jack28. The plug 44 is then inserted in ack 54 and either the operator orthe person at the extension telephone may transmit the proper number tothe master telephone which leads to the main exchange. The operator atthe main exchange then connects the master telephone with the party atthe number called in the usual manner thereby completing the call' fromthe extension telephone to the outside party. hen the call is ended theparty at the extension hangs up the receiver 26 causing supervisory lamp49 to be lighted as described above. The operator then withdraws plugs43-44 thereby deenergizing magnet 21 to restore switch hook 11 to openthe circuit of line L thereby giving the usual disconnect signal to theoperator at the main exchange.

Calls from one extension telephone to another are handled as in theordinary branch exchange. The raising of the receiver of an extensiontelephone lights line lamp 34 until plug 43 is inserted in jack 28. Theoperator upon learning that a call is being made to one of the extensiontelephones inserts plug 44 in the jack of the extension telephone calledresulting in the lighting of supervisory lamp 64. The operator thenactuates ringing key 74 which is similar to key 71. As soon as the partycalled answers lamp 64 will be extinguished. When the call is ended thehanging up of the receiver at either end will cause one of thesupervisory lamps to be lighted to signal the operator to disconnect thecord circuit.

In order to make the extension telephone available when the operator isabsent as for instance after regular working hours means are providedwhereby the extension telephones may be connected to the repeatingtelephone M so that a call may be made from any one of the extensiontelephones as N--N out to the distant exchanges over conductors 7576 towhich the extension telephones as NN may be connected by switches 77.Conductors 75 are connected to the talking conductors 16 of theconnecting telephone M and conductor 76 is connected to the conductorleading to the electromagnet 21. Each of the extension telephones isprovided with a contact member 81 adapted to be engaged by a springcontact 82 adapted to be closed on contact 81 by the receiver hook ofthe ex tension telephone. The spring contact 82 is connected to ground83 so that when the receiver 26 is removed from its hook a circuit isestablished from battery 23 through coil 21, conductor 78, contacts81-82 to ground 83 thereby causing the electromagnet 21 to be energizedto establish the electrical communiating connections in the telephones Mand M. When switches 77 are closed the extension telephones are providedwith talking current from the battery 33 through impedance coil 31 whichtherefore serves a double function since it also acts as'a relay forline signal lamp 34 when the link circuit is em ployed.

Thus when a call is to be extended from a telephone as N or N directlyto the outgoing line L by connect'ng and master telephones M-M, theparty calling simply removes receiver 26 from its hook whichautomatically causes the proper connections to be made in the connectingtelephone M, and raises the receiver hook of the master telephone toconnect it to line L leading to the main exchange. As soon as theexchange operator responds the party calling gives the operator thenumber desired and the call is completed in the usual manner. WVhen thecall is ended the hanging up of the receiver of the extension telephonedisconnects the connecting telephone and restores the receiver hook ofthe master telephone to its normal or down position thereby giving theexchange operator the usual disconnect signal.

A call coming from the master telephone may be answered directly from anextension telephone when switches 77 are closed. A person at anextension telephone hearing the bell of the master telephone ringing mayby raising the receiver of the extension telephone automaticallyestablish the proper connections in the connecting and master telephonesM and M as described above and communicate with the party calling. Whenthe call is ended the hanging up of the re ceiver at the extensiontelephone again disconnects the connecting and master telephone andgives the exchange operator the disconnect signal as described.

It will be understood that the embodiment of the invention describedabove is merely illustrative and that many modifications may be madeWithout departing from the spirit and scope of the invention.

What I claim as new and desire to protect by United States LettersPatent is:

1. An apparatus for mechanically interconnecting separate telephonesystems comprising a master telephone having a transmitter and receiver,a connecting telephone having a. transmitter and receiver in soundtransmitting relation to the receiver and transmitter respectively ofthe master telephone, an extension telephone electrically connected tothe connecting telephone, and meansresponsive to the movement or" thereceiver hook of the extension telephone for moving the receiver hookout the master telephone whereby communication is established betweenthe extension and master telephones.

2. An apparatus for mechanically interconnecting separate telephonesystems comprising a telephone electrically connected to one system andhaving a transmitter and receiver, a connecting telephone having atransmitter and receiver in juxtaposition to the receiver andtransmitter respectively of the first mentioned telephone, an extensiontelephone electrically connected to said connecting telephone, anelectromagnet for placing the first mentioned telephone in communicativecondition, a separate circuit for said electromagnet leading to theextension telephone, and means associated with the extension telephonetor closing said circuit when the extension telephone is placed incommunicating condition.

3. An apparatus for mechanically interconnecting separate telephonesystems comprising'a master telephone electrically connected to onesystem, a connecting telephone mechanically associated therewith 'toreceive and transmit messages thereto, an extension telephoneelectrically connected to the connecting telephone, an electromagnet,means associated with said electromagnet for placing both the mastertelephone and the connecting telephone in communicating condition whenthe electromagnet is energized, and means associated with the extensiontelephone for causing the energization of said electromagnet.

t. In an apparatus of the class described a master telephoneelectrically connected to a telephone system, a connecting telephonemechanically associated therewith to receive and transmit messagesthereto, an extension telephone, a cord circuit, and means for placingthe master telephone and connecting telephone in communicating conditionwhen the cord circuit is electrically connected to the extensontelephone and the connecting telephone.

5. In an apparatus of the class described a master telephoneelectrically connected to a telephone system, a connecting telephonemechanically associated therewith to receive and transmit messagesthereto, an extension telephone, a. cord circuit, and means for placingthe master telephone and connecting telephone in con'nnunicatingcondition when the cord circuit is electrically connected to theconnecting telephone.

6. In an apparatus of the class described a master telephone, aconnecting telephone mechanically associated therewith, anelectromagnet, movable means associated with said electromagnet forplacing the master telephone and connecting telephone in communicatingcondition, a cord circuit, and means for energizing said electromagnetwhen the cord circuit is electrically connected to the connectingtelephone.

7. In an apparatus of the class described an extension telephone, amaster telephone electrically connected to a telephone system, arepeating telephone mechanically asso ciated with the master telephoneand electrically connected with the extension telephone, anelectromagnet, movable means asso ciated with said electromagnet forplacing the repeating telephone and master telephone in communicatingcondition, and means associated with the extension telephone forenergizing and decnergizing said electromagnet.

8. In an apparatus of the class described an extension telephone, amaster telephone, a repeating telephone mechanically associated with themaster telephone, a-cord circuit connectible between the extensiontelephone and the repeating telephone, means for placing the repeatingtelephone and master telephone in communicating condition when the cordircuit electrically interconnects the extension and repeatingtelephones, means for directly interconnecting the extension telephoneand the repeating telephone without the interposition of the cordcircuit and means associated with the extension telephone for actuatingthe means for placing. the repeating telephone and master telephone in.communicating condition when the extension telephone and repeatingtelephone are directly interconnected.

9. In an apparatus of the class described a plurality of extensiontelephones, a cord circuit selectively connectible to any of saidextension telephones, a master telephone electrically connected to atelephone system, a repeating telephone mechanically associated with themaster telephone, means for establishing electrical communicatingconnections in both the master and repeating telephones, said meansbeing actuated in response to connecting the cord circuit with therepeating telephone.

10. In an apparatus of the class described a plurality of extensiontelephones, a master telephone electrically connected to a telephonesystem, a repeating telephone mechani- 'ally associated with the mastertelephone, a cord circuit for selectively interconnecting a pair ofextension telephones or connecting an extension telephone to therepeating telephone, and means for simultaneously establishingelectrical communicating connections in the repeating telephone and themaster telephone to provide coi'nn'innication between the mastertelephone system and the extension telephone.

11. In an apparatus of the class described an extension telephone, amaster telephone connected to a telephone system, a repeating telephonemechanically associated therewith, means for directly interconnectingthe extension telephone with the repeating telephone, an electromagnetfor establishing communicating connections in the repeating and mastertelephones, and a spring contact in the extension telephone for causingthe energization of said magnet in response to movement of the receiverhook of the extension telephone.

12. In an apparatus of the class described, a master telephone in atelephone system, a connecting telephone in a second system said masterand connecting telephones being mechanically associated to transmitsounds from one to the other, an extension telephone electricallyconnected to the connecting telephone, a receiver and hook in saidextension telephone, and means responsive to removing said receiver fromsaid hook for establishing communicating connections in the con nectingand master telephones.

13. In an apparatus of the class described a telephone system, a mastertelephone connectible in said system, an extension telephone system, arepeating telephone connectible in said extension system andmechanically associated with the master telephone, an extensiontelephone connectible in said extension system, means responsive toconnecting the extension telephone to the extension system forconnecting the repeating and master telephones to their respectivesystems, said repeating and master telephones being restored to theirdisconnected conditions when the extension telephone is disconnectedfrom the extension system.

14. In an apparatus of the class described a master telephone, arepeating telephone mechanically associated therewith in soundtransmitting relation, an extension telephone having a receiver andreceiver hook, a line signal lamp, means for lighting said lamp when thereceiver of the extension telephone is removed from its hook, a cordcircuit for interconnecting the extension and repeating telephones, asupervisory lamp in said cord circuit, means for lighting saidsupervisory lamp when the cord circuit is connected to the extensiontelephone and the receiver of the extension telephone is on its hook andextinguishing said lamp when the receiver is removed from its hook, andmeans for establishing communicating connections in the repeating andmaster telephones when the cord circuit is connected to the repeatingtelephone and restoring the repeating and master telephones to theirnormal condition when the cord circuit is disconnected from therepeating telephone.

15. In an apparatus of the class described a master telephone in atelephone system, a repeating telephone in a secondtelephone system,said repeating telephone being mechanically associated with the mastertelephone in sound transmitting relation, and remote control means forestablishing communicating connections in the repeating and mastertelephones.

16. In an apparatus of the class described a pair of telephoneselectrically interconnected by a line and each having a transmitter anda receiver, and means for electrically connecting the receiver and thetransmitter in one telephone to the line in response to making similarconnections in the other telephone.

17. In an apparatus of the class described a pair of telephones eachhaving a receiver and a receiver hook, a magnet associated with one ofsaid telephones for actuating the re-' ceiver hook, said magnet beingenergized in response to the position of the receiver hook of the othertelephone.

18. In an apparatus of the class described a telephone system, a pair oftelephones associated therewith each having a receiver and a hooktherefor, an electromagnet for actuating the hook of one of saidtelephones for establishing communicating connections in said telephone,and a separate circuit including said electromagnet and leading to theother telephone whereby said electromagnet may be remotely controlled.

19. In an apparatus of the class described a master telephone connectedto a main telephone system, a repeating telephone mechanicallyassociated therewith in sound transmited therewith in sound transmittingrelation,

an extension telephone, a cord circuit for interconnecting the repeatingand extension telephones, a signal means in said master telephone, meansfor interrupting said signal means and establishing communicatingconnections in the repeating and master telephones in response tointerconnecting the cord circuit with the repeating telephone.

21. In an apparatus of the class described a main telephone circuit, amaster telephone connected thereto, a repeating telephone associatedwith said master telephone, an electromagnet, a pair of receiver hookssimultaneously operable'by said electromagnet to place said telephonesin communication, a grounded battery for energizing said magnet, and alead extending from said electromagnet to a remote point for-controllingthe energization of said magnet.

In witness whereof, I hereunto subscribe my name this 24th day of May,1929.

RUSSELL L. MAURER.

